1. I am blessed with a dually-dysfunctional bladder: it wants to let stuff out when I want to hold it in, but it won't empty completely when I ask it to. I can usually persuade it to empty most of the way by gently pressing on and massaging it with my hand. That's fine when I'm standing at a urinal, but when I'm at my desk it might look a little weird. The upshot is that the bag will be happy to catch whatever my bladder decides to let out, but in order to truly empty I'll still need to adjourn to the men's room. If I don't, I run the risk of developing a bladder infection--something I haven't had a problem with yet.
2. I need to figure out how to keep the bag up by my knee instead of down by my ankle. As the bag fills, of course, it gets heavier and starts creeping down and pulls at the "condom."
3. Walking with a fullish bag, especially one that's slid down a bit, causes an audible gurgling/sloshing sound.